The invention relates to the field of satellite direct radio broadcast, and in particular to a satellite-based broadcast communication system employing frequency division multiplex uplinks and time division multiplex downlinks and for broadcasting and audio (voice and music) programming.
Early satellite communication systems used space-based radio frequency transponders which acted as simple repeaters. In one typical scheme, multiple sources each transmit at a separate uplink carrier center frequency (uplink FDMA), and the satellite transponder repeated each signal at a separate downlink carrier frequency (downlink FDMA). In another typical scheme, multiple sources each transmit bursts at the same carrier frequency in a coordinated fashion so that bursts from different transmitters do not collide (TDMA), and the transponder repeated all signals in a single downlink carrier. Still other schemes utilize multiple antenna beams and on-board-the-satellite switching so that signals in one uplink beam could be controllably switched to a selected downlink beam.
Many prior systems require substantial transmit and/or receive equipment. Furthermore, despite the various types of system architectures, there has not been implemented a system suitable for direct broadcast of audio radio programming to low-cost consumer radio receivers.